Modelling of the torsional IR spectra of the HSSSH, DSSSH, and DSSSD molecules

Potential and kinetic interaction of two internal tops in molecules belonging to C2v(M) molecular symmetry group

“…However, in the experimental works noted above, it was not possible to detect the splitting of spectral lines due to tunneling between equivalent configurations of molecular conformers. This is also consistent with the results of works [7,35,33,34] according to which the tunneling splittings of the ground vibrational states in the trans and cis conformers of the HSSSH, HOSOH and HOOOH molecules are very small (the maximum calculated value of the tunneling splitting was found in the cis conformer of the molecule HOOOH and ranged from 3*10 -7 [34] to 1*10 -6 [33] cm -1 ). As far as we know, only in [4] the tunneling splitting of the first excited torsional state of the C 6 H 4 (OH) 2-ortho molecule was experimentally recorded, the value of which was 1.041*10 -5 cm -1 .…”

“…Among them, noteworthy works [48][49][50][51] in which the structure, conformational composition and spectroscopic constants of the molecules HSSSH [48,49], HOSOH [50], and HOOOH [51] are analyzed. The experimentally determined values of rotational constants, potential barriers and relative energies of molecular conformers are in good agreement with the calculated values in the above-mentioned works [7,35,33,34]. However, in the experimental works noted above, it was not possible to detect the splitting of spectral lines due to tunneling between equivalent configurations of molecular conformers.…”

“…Internal rotation in molecules (one of the types of large amplitude motion (LAM)) continues to attract the attention of researchers today [1][2][3][4][5][6][7]. This is due to the important role that internal rotation plays in determining the thermodynamic properties of molecules [1], as well as in the formation of the fine structure of rotational and vibrational-rotational absorption bands [8][9][10].…”

“…We have previously calculated the two-dimensional PES and torsional spectra of several molecules containing two hydroxyl groups (HO(CH 2 )OH (II) [31,32], HOOOH (III) [33,34], HOSOH (IV) [35] and C 6 H 4 (OH) 2-ortho (I) [36]), as well as two molecules containing two thiol internal tops (HSOSH (V) [37] and HSSSH (VI) [7]). All calculations for the molecules listed above were performed at the MP2/CBS(T,Q) [38][39][40][41][42] level of theory.…”

Torsional IR spectra of three conformers of the resorcinol molecule

“…Let us recall that the RES molecule belongs to the same molecular symmetry group (C 2V (M)) as the CTL molecule. Previously, we calculated the torsional IR spectra of a number of molecules (HO(CH 2 )OH, HOOOH, HOSOH, HSOSH, HSSSH) belonging to this molecular symmetry group [37][38][39][40][41]. Based on an analysis of literature data and relying on the experience gained from analyzing torsional vibrations of similar molecules, we performed calculations of the torsional states of the RES molecule.…”